#include<stdio.h>
int main()
{
    double a,b,c;
    scanf("%lf%lf%lf",&a,&b,&c);
    if(a+b<=c || a+c<=b || b+c<=a)
    {
        printf("It isn't triangle\n");
    }
    else if((a==b&&a!=c)||(a==c&&a!=b)||(b==c&&b!=a))
    {
        printf("isoceles triangle\n");
    }
    else if(a==b&&a==c&&b==c)
    {
        printf("equilateral triangle\n");
    }
    else if(a*a+b*b==c*c||a*a+c*c==b*b||b*b+c*c==a*a)
    {
        printf("right-angled triangle\n");
    }
    else
    {
        printf("arbitrary triangle\n");
    }
        return 0;
    }
